[patch 47/60] sparc64: Fix end-of-stack checking insave_stack_trace().

[Greg KH]

2.6.26-stable review patch.  If anyone has any objections, please let us know.

------------------
From: David S. Miller <davem@xxxxxxxxxxxxx>

[ Upstream commit 433c5f706856689be25928a99636e724fb3ea7cf ]

Bug reported by Alexander Beregalov.

Before we dereference the stack frame or try to peek at the
pt_regs magic value, make sure the entire object is within
the kernel stack bounds.

Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 arch/sparc64/kernel/stacktrace.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/arch/sparc64/kernel/stacktrace.c
+++ b/arch/sparc64/kernel/stacktrace.c
@@ -25,13 +25,15 @@ void save_stack_trace(struct stack_trace
 
 		/* Bogus frame pointer? */
 		if (fp < (thread_base + sizeof(struct thread_info)) ||
-		    fp >= (thread_base + THREAD_SIZE))
+		    fp > (thread_base + THREAD_SIZE - sizeof(struct sparc_stackf)))
 			break;
 
 		sf = (struct sparc_stackf *) fp;
 		regs = (struct pt_regs *) (sf + 1);
 
-		if ((regs->magic & ~0x1ff) == PT_REGS_MAGIC) {
+		if (((unsigned long)regs <=
+		     (thread_base + THREAD_SIZE - sizeof(*regs))) &&
+		    (regs->magic & ~0x1ff) == PT_REGS_MAGIC) {
 			if (!(regs->tstate & TSTATE_PRIV))
 				break;
 			pc = regs->tpc;

-- 
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